Sowing very small seeds: advice needed

[mmcavall]

I have once tried Strombocactus and Blosfeldia, and seeds disappeared in the mix, I could’nt even see I they germinated (some of the Strombos germinated but disappeared thereafter).
I have some really tiny seeds to sow again, such as Parodia catamarcensis, Strombos and Aztekium.
Could anyone give me some advice?
Is it a good idea to put some wet paper towel in the surface of the mix, and let the seeds germinate on it? Or maybe fine sand as “top dress”, to avoid the seeds to disappear inside the mix?
Any help will be much appreciated,
Thanks

[ElieEstephane]

I remember reading this a while back:
http://www.cactusstore.com/article_11/G ... -Seeds.htm

[keith]

I use fine sand at the top of the pot and drop seeds out of the container on the sand and water them in with a light spray.

[mmcavall]

Thank you very much, Elie and Keith, this was very helpful

[Aiko]

I use a fine mix of sand and loam, 50% each. It is probably not wise to use rough and big material for sowing. The mixture will be cooked in a pan first, and when still hot and wet, I scoop the mix into the pots. Then I just springle the seeds on top of it. And that's it. Only bigger seeds I tend to push into the soil a bit, but small seeds I just leave them as they are.

For Blossfeldia and Aztekium however I do prefer to keep the freshly sown pots into an air tight bag for at least one year. Otherwise the seedlings will die off one by one soon after germination. Keeping them in a locked bag makes sure they don't dry out too fast.

[Hanazono]

I use a normal mix for seed germination but a tissue paper is put on the mix before sowing seed.
I spray water over the tissue paper then sow seeds over the wet tissue paper.

[mmcavall]

Thank you very much, Aiko and Frank. I have seeds sufficient to test both methods, fine sand and paper tissue. Hope I can come back here with good results to show. Thanks a lot.

[theJrnyconts]

I had heard that smaller seeds need more light to germinate. I put this to the test with some mammiliria seeds. I used fine sand as the top layer to cover some seeds, half way cover seeds, and have some sit on top. The seeds sitting on top greatly out performed the seeds that were covered. It seemed to be 50/50 on seeds halfway covered. Since mine are in a closed environment, I don't even bother misting the sand on top. The same happened with my saguaro seeds. Sitting on top was by far the best germination rate.

[mmcavall]

Thank you jrnyconts and welcome to the forum

[Theral]

With super tiny seeds I simply sow them directly on top of the soil. Once they germinate and grow larger you can sprinkle additional sand or soil on top to help support them if they're not rooted very deeply.

I started some Blossfeldia this way a couple months ago and they're so miniscule that they don't need any extra soil. They're planted in mostly fine crushed pumice with a bit of coco coir and soil, with about half a centimeter of the same mix sifted finely on top.

IMG_20190408_082030-1280x960.jpg (80.58 KiB) Viewed 3519 times

[mmcavall]

Thank you Theral, I assume that it works because of the soil in your mix. It doesn't let the seeds pass through, so they don't disappear inside the mix. Thanks for sharing.

[abhikjha]

Hi all, sprinkling seeds on top of the soil resulted good germination rate but also the few seeds started growing roots on surface.

I am thinking to open the box once germination is over in couple of weeks, fix the roots in small holes and cover the substrate using small gravels or grit. Remove excess humidity by removing water droplets on lid, mist them again with hydrogen peroxide mixed water and cover them again for next at last 1 year.

This sounds fine?

[LateBloomer]

This is an old thread but I’ll also share my experience... what I used for aztekium sp. was lava sand. In the states I bought a large bag online pretty cheap but if you have lava rock just crush it until it’s a fine sand. The soil I mixed very little amount of soil just for the nutrients but can just water with a very weak fertilizer.

I kept them in the mix for 6 months no issues but had to give away cause was moving... with about a month seedlings are large enough to graft if you have experience.

I really like the tissue paper sowing method as it seems the easiest and effective way. I’ll attempt when I get around to sowing some aztekium